Refillable fuse



July 29, 1924.

M. J. SANDIN ET AL REFILLABLE FUS E WITNESSES:

ATTRNEY Patented July 29, 1924.

UNITED s'rATi-:s

/ 1,502,885 PATENT OFFICE..

HAUBITS J. SANDIN, OF WILXINSBUBG, AND JOHN B. MAoNEI'LL, OF PITTSBURGH, PENNSYLVANIA. ASSIGNORS TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION F PENNSYLVANIA.

REFILLABLE FUSE.

Application led January 12, 1920, Serial No. 351,000. RenewediFebruary 2, 1924.

To al] ltlf/m, it may concern Be it known that we, Mxt'nrrs J. SANDIN, a citizen of the United States, and a resident of ll'ilkinsburg, in the county of Alle- 5 hen and State of Tennsylvania, and JOHN l li ACNEILL, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvel0 ment in Refillable Fuses, of which the following is a specification.

Our invention relates to fuses and particularly to retillable cartridge fuses.

Une object of our invention is to provide a cartridge fuse having means for so controlling the escape of 'arc gases as to prevent damage to the cartridge. to ensure a proper relatively-high'internal pressure to lreduce the arc and to so cool thev escaping gas as to prevent the emission of flame.

Another object of our invention is to provide a cartridge fuse adapted 'for use with the standard fuse-terminal clips vthat shall employ one or a plurality of interchangeable members to form an auxiliary coolingchamber or chambers therein .of predetermined cooling-surface area for a fuse or fuses of given capacity.

Another object of our invention is to provide means whereby certain relativelysmall, normally-loose parts of a cartridge fuse shall be so permanently associated with other relatively-large parts as to facilitate their manipulation and reduce), the likelihood of the loss thereof.

The present standard formsrof cartridge fuses and the stationary terminal clips therefor are of certain dimensions and constructions for diven rating. These features have resulted rom relatively long practice ,dur-

ing which the roper proportions and forms y have been deve oped. but the features yof preventing the disruption of certain parts and the emission of llame havenot, to the 'best of our knowledge, been developed to very 'high degrees of eiliciency and economy.

This has probably been due to the limitations imposed by the forms and dimensions which were arrived at in the attempts to obtain effectiveness in other features, such as conductivity and mechanical strength.

It has been found that a high internal pressure is desirable to facilitate extinguishingy the arc but this pressure mustv not be too high because disruption of the cartridge and other damage and loss may ensue.

Further', the emission of flame. even though small in amount and extending to only'a short distance from the cartridge, is an undesirable feature.

Reference. may be had to copending application, Serial No. 350,948, filed January 12, 1920, by M. J. Sandin and assigned to the llvestinghouse Electric` & Manufacturlng Co. in which is disclosed a cartridge fuse fork accomplishing substantially the same results but which is of different operation and construction.

In practicing our invention, we provide a renewable cartridge fuse constructed in ac- -cordance with standard f' requirement in which there 'shall be definite relations between the internal pressure, the rate of gas escape and the degree towhich the gas is cooled before it reaches the outer air or surrounding objects.

This is accomplished, irrespective of space and other limitations of the standard cartridge fuse, and, at the'same time, permits the fuse to be manipulated in a. simple and expeditious manner. l

Figure l of the accompanying drawings is a side view, partially in elevation and partially in-section, of a cartridge fuse embodying our invention; Fig. 2 is a plan view, partially in section, of a portion of one end thereof; Figs. 3, It, 5, 6, 7 and 8 are detail views of various washers embodied in theV device of Figs. 1 and 2; Fig. 9 is a view, similar to Fig. 1, of a modified form of fuse cartridge embodying our invention, and Figs. 10 and 11 `are detail views of a modified form of washer employed in the device of Fig. 9.

"In-general, pur device comprises an insulating casing l, end ferrules 2, terminal blade members 3 and a fusible element 4.

,Themembers 3 have outer portions 5 for cooperation with the usual vstandard fuse clips (not shown) and smaller inner-end portions 6 to' which the element 4 is attached, as by bolts or screws Z and nuts 8.

Washers 9 and 10, preferably of diameters to snugly tit the interior of the casing 1 have apertures 11 and vl2, respectively, that conform to the smaller end 6.of kthe member 3, are placed on the end 6 against the end 5 and are swaged or otherwise sev a positioning lug 16 for insertion in a notch (not shown) in the end of the casing.

The ywasher 14 is secured to the washers 9 and 10 by screws 17 ythat have intermediate portions 18 of reduced diameteropposite which the washer 14 has upset or swaged portions 19 to prevent the withdrawal of the screws 17. through the washer 14.. Thus, the screws 17, while readily turnable in the1\washer 14 to permit` the latter to be attached to and detached from the washers 9 and 10, may not be"separated from the washer 14. An inwardly-extending tlange720 oni the ferrule 2, that is preferably-threaded to' the casing 1, engages the .washer 14 to hold the terminal parts in Irespect to tlie`notches 24 and serve to con-v bers engaging. in ielatively-broad-surface reposition.,

The washer 10 has portions 21 and 22 on its faces that are countersunk or depressed except at the perimeter of the washer, at narrow portions surrounding the ,aperture 12 and at portions 'surrounding the holes 23 for the reception of the screws 17. The portions 21 and 22, in cooperation with the washers 9 and 14, provide gascooling chambers of sufficient area to s o cool the gases as to .prevent the emissioni of flame from the cartridge.

To provide communicating passages from the inteio'r of the fuse casing to the gas chambers between the washers 9 and 10, the

Washer 9 is provided with o enings, preferably notches 24 that extend rom the perimeter) to points on the diameter thereof Within the rim of the washer 10. Apertures 25 in the reduced central body portion of the washer 10 are angularly displaced about the axis of the cartridge `with duct arc gases to the chamber between the washers l0 and 14.. From the chamber between the washers 10 and 14, the gases are conducted to the outer air through `apertures 26 'in the Washer -14 that are -gas will rupture angularly `displaced with respect to theI apertures 25 in the washer 10.

- In operation, when the element 4 is volatilized, afquantity of gas, under relatively great pressure, is generated. -If the escape passages are too restricted, the force of this ome portion of the cartridge. It is, therefore, imperative that the pressure be reduced. On the other hand, alrelatively high pressure is desirable jto vassist in quenchin `the arc. The mean between these opposing factors lies in having the escape passages of asdefinite predetermined size for a fuse of given capacity. Also in a fuse of given capacity land therefore ,of certain Haine-generating must be provided .to preventl any flame reaching the exterior of the cartridge.. It

is not suiiicient to merely provide openings to permit the escapeof gas. The openings should be in accord with the explosive force, in which case the are is held t0 a minimum, at its inception,for a fuse' of given capacity and a cartridge of given strength. The area of the cooling surfaces at the portionsv 21 and 22 of the washer 10, in co-operation with the washers 9 and 14, is then of a predetermined size to cool the flame of this y predetermined arc, there being definite relations between internal pressure, rate of es- 30 cape of the -gas and the amount ofcooling.- 4The device shown in Fig. 9 is similar to y the above described device in that it employs the washers 9, 10 and 14 in the same manner but it also utilizes a washer 27 that 35 is countersunk or depressed on one face only at its central portions 28 and is disposed between the washers 10 and 14. This provides additional-cooling areal for afuse of higher current-carrying capacity that generates a greater amount of gas. Compensation for the higher explosive force A may be attained. by increasing the number and sizes of the openings 25 and 26. i While we have shown and described articularforms of our invention, it is obvious that the parts thereof'ma-y be changed and used in various other combinations and relations, without departing from the spirit and scope thereof, 'as set. forth in the appended claims.

XVe claim as our invention: 1. A cartridge fuse 'comprising three members engaging 1n relatively-broad-surface relation, the central one of which has its per- `iiiieter and 'intern'iediate portions of different thicknesses to provide a gas-cooling chamber terminal lll a second -washer havin a countersun t surface portion engagiigsai terminal washer, said countersunk portion constituting\ a gas-coolinfr chamber between isaid washers, and' said opening constituting-a communicating pas- 'sa e betii'een theouter surface ofthe termina washer and said chamber. y.

4. A cartridge fuse comprising a terminal washer havin notched periphery and a second washer avin a countersunk surface engaging said terminal washer, said countersunk portion constituting 'a gascooling chamber between said washers, and said notch constituting a communicating pas- Il sa'ge between the outer edge of 'the terminal washer and'l said chamber.

-5. A refillable cartridge fuse comprising a terminal washer having a notched periphery', and a second washer having a countersunk surface portion engaging said terminal Washer and an opening through said counterl sunk portion, the latter portion constituting a gas-coolingfchamber between said Washers and the vsaid notch, and said opening constitiiting terior of the washers.

6. A cartridge fuse comprising a casing, a terminal'membertherefor, an inner washer on the terminal member having a peripheral notch, an intermediate washer on the terminal member having an opening therethrough n'al members, means rigidly secured to the and a countersunk face communicating with said notch, an apertured outer washer on the terminal member yenga g the end of the casing, means for holdlng said washers together, and means for holdingthe washers and the terminal member in position with respect to the casing, the arrangement providing a unitary removable structure of substantially'minimum length having a tortuous gas-escape path and a gas-cooling chamber therein.

7. A retillable cartridge fuse comprising arcasing, anl end ferrule thereor, 'a knifeblade terminal member, a plurality of washers on said vterminal member, one of which is larger than the interior diameter and engaged to the end of thecasing by said' ferrule, and irremovable `means on said ylarger washer -for holding all of .said

washers together. l

8. In a reillable cartridge fuse, the combination of a casing, terminal members therefor, a fusible element, means for removably' securing saidelemcnt to the termiterminal members for arc gases in communicating passages to the ina path `transversely of the casing, and removable means independent of the said securing means and detacliably secured to the second said means for aligning and center- .ing the terminal members and means for 10. A cartridge fuse comprising a tubularcasing, a terminal blade-member provided with a pair of washers having a gas-conducting and cooling chamber therebetween,

a third washer removably mounted upon the blade member for positioning the latter with respect to the casing and a. ferrule for clamping the removable Washerv to the casing;

11. A cartridge fuse comprising a tubular casing, a terminal blade member pro-A vided with a pair of Washers having a' gasconducting chamber therebetween, and secured to theblade member, a thirdv washer'4 removably mounted u the blade member for positioning the bliiilne member with respect to the casing,- a Yferrule forclamping the removable washer to the casing and means for preventing separation of the blade member and the removable washer.

In testimony whereof, we have hereunto subscribed .our names this 31st day of December, 1919. n Y

J OHN B, MACNEILL.

,VMAURITS J. SANDIN; 

